Exempi is an implementation of XMP. Version 2.x is based on Adobe XMP SDK and released under a BSD-style license like Adobe's. The 3 clause BSD (aka New-BSD) license is compatible with GPL. The licensing is kept identical in order to allow two-way merging of the code (ie sending our change to the XMP SDK to Adobe for integration).

The API is C based and means to be used from any language and be easier to maintain ABI stability.

The overall changes include:

STABLE C API/ABI for the library, instead of a C++ template based version.

GNU friendly build system based on automake.

Code changes for UN*X systems compatibility.

Architecture support for 64-bits (x86_64) and others.

Test suite.
There is also a work in progress "exempi" command line tool starting in 2.2.0